Software counterfeiters pass on Windows Vista and instead prefer to pirate Windows XP, a Microsoft Corp. attorney said today, outlining a practice that tracks with the leanings of many of the company's customers.

"Historically, counterfeiters tend to focus on the 'n-1' version of software," MacNaughton said. "Because of the more robust antipiracy and security features in Vista, most sophisticated piracy rings still continue to focus on XP. But that's changing over time."

That pirates have stuck with XP -- which retains the bulk of the Windows operating system's market share -- is "very consistent with what we've seen in counterfeiting in the past," said MacNaughton. "There's usually a lag of between one and two years [before they can] figure out how to replicate those antipiracy and security features."

Counterfeiters currently copy Office 2003 rather than the newer Office 2007 for the same reasons, she said.

MacNaughton also touted the day's announcements of new initiatives and lawsuit filings scheduled to take place in 49 countries, ranging from Argentina to the U.S. "As counterfeiters have gotten more sophisticated, we have realized that this is not a situation that we can address alone," she said. "And we want to stress [today] the collaboration with Microsoft's partners and customers, and governments."

In the U.S., Microsoft filed 20 new lawsuits in federal court against software resellers that, according to the company's allegations, either sold pirated copies of Microsoft Windows XP Professional and Office or installed the counterfeit software on new PCs. Nine of the lawsuits were filed in California; two each were filed in Ohio, Oregon and Texas; and others were filed in Connecticut, Florida, Louisiana, Minnesota and New York.

MacNaughton also said that Microsoft is planning on another antipiracy educational effort early next year to make sure that customers know Windows XP's lifespan is coming to an end. "We're expecting that counterfeiters will attempt to fill the void at XP's end of sales," she said.

Microsoft will halt Windows XP Professional sales to small mom-and-pop computer sellers after Jan. 31, 2009. Larger computer manufacturers, such as Dell Inc. and Hewlett-Packard Co., however, will be able to obtain XP media for "downgrades" from Vista Business and Vista Ultimate licenses through the end of July 2009. Microsoft only recently said that it would extend shipments of XP to OEMs; previously, it had said it would stop the practice in January.

According to MacNaughton, Microsoft will roll out a campaign in early 2009 that will remind people of XP's demise and warn them that copies they obtain after those end-of-sale dates could be counterfeit. "We're planning [a campaign] in January or February to make sure our customers know what our rules and policies are about Windows XP," she said, "to make sure they understand what may be illegitimate and what may be legitimate. We want to make sure that the XP they might be getting is genuine."

Data compiled in August by a Florida developer of Windows performance metrics software showed that more than one-third of all new PCs are still downgraded to Windows XP from Vista, either by the user after purchase or by the computer maker at the factory.